The subject matter of the present invention is a method for the continuous production of potassium tert-butoxide by the reaction of aqueous potash lye with excess tertiary butanol in a column in the presence of a withdrawing agent. In this method the potash lye and the tert-butanol are put into the top of the column and the water that forms in the reaction, as well as the water introduced by the reactants, is distilled out through the top by means of the withdrawing agent. In the boiler a solution of the potassium tert-butoxide in tert-butanol is formed; this solution is continuously withdrawn and the anhydrous salt is obtained from this withdrawn solution.
In the method described in U.S. Pat. No. 45 77 045 for the preparation of potassium tert-butoxide, the withdrawing agent used is cyclohexane or n-hexane. Furthermore, the amount of the withdrawing agent is selected such that at least half of the gas mixture present in the middle of the column is tert-butanol. In operating according to this method a potassium tert-butoxide is obtained which is anhydrous and has a maximum content of 0.8% KOH; however, the possible throughput of aqueous potash lye per unit of time is extremely low, so that the yield per unit of capacity and time is unsatisfactory in this process.
The problem therefore was to devise a continuous method for the production of anhydrous potassium tert-butoxide which would make it possible with the same expenditure of energy as in the method of U.S. Pat. No. 45 77 045 to increase the KOH throughput per unit time and at the same time obtain a product having at least the same qualities as the known products.